1. Field of the Invention
The present invention is directed to gel electrophoresis, and in particular, to a pre-cast vertical monolithic gel electrophoresis system and an electrophoresis method using the present monolithic system.
2. Description of Related Art
Gel electrophoresis is known for separating and purifying protein, peptide DNA, RNA, and a variety of electrically charged macromolecules for the study thereof, or as a preparative step for subsequent analytical procedures. For instance, gel electrophoresis is often used to separate and purify molecules for protein purity verification, protein identification, subsequent DNA sequencing, blotting procedures, mass spectrometry, PCR, RFLP, cloning, or other known techniques for further characterization.
In vertical electrophoresis, a gel matrix is placed in a buffer-filled electrophoresis tank such that the gel is submerged just beneath the buffer surface vertically. The gel matrix is of a material having both a composition and porosity suitable for the specific molecular weight, size and composition of the target molecules to both contain and separate these target molecules. The gel matrix also has wells for receiving alloquots of the target sample to be tested. The electrophoresis tank has cathode and anode terminals on opposite sides of the gel matrix, such that, once the target samples reside in the gel matrix, an electric current is applied to the matrix for generating an electric field. This electric field separates the charged molecules suspended in the gel matrix, whereby negatively charged molecules move in bands through the matrix at different rates toward the anode, while positively charged molecules move in bands through the matrix also at different rates toward the cathode.
In a conventional electrophoresis assembly, the electrophoresis box is composed of two separate flat plates separated by spacers for holding a gel. The electrophoresis apparatus is assembled by providing a gel either vertically or horizontally between these flat plates. This gel may be a pre-cast (i.e., prefabricated) gel that is removed from its packaging and placed between the two flat plates, or it may be mixed by the user assembling the electrophoresis apparatus, poured into a gel mold between the plates and then allowed to set for several hours to form a gel. The electrophoresis tank also includes two reservoirs for containing a buffer solution, whereby each reservoir is on opposite sides of the gel and has an electrode therein. Once the gel is provided between the plates, a buffer solution is poured into each of these reservoirs so that the buffer covers the gel and the electrodes reside within the buffer. With the samples to be tested residing in wells of the gel, an electric current is then applied to the assembly via the electrodes to generate an electric field across the gel for separating the charged molecules in such gel. The gel is then removed for subsequent analytical procedures, and the equipment must be thoroughly washed for reuse.
However, these conventional gel electrophoresis assemblies and approaches are lengthy, and require a significant amount of processing steps and skill in preparing the gel, assembling the apparatus and running the gel. These approaches also require a large amount of buffer to run the gel, typically greater than 750 ml, and are prone to leakage due to the apparatus being improperly assembled. Additionally, these conventional gel electrophoresis systems that include the buffer tank, various clamps and gel holders, buffer dam and tank cover, and supplies for running gels are expensive, bulky and require washing and maintenance thereof after performing an electrophoresis run.
Accordingly, a need continues to exist for improved electrophoresis assemblies that are easy to use, require minimal processing and handling steps, are structurally and mechanically stable, time efficient, and are low cost.